Giant cell = a type of cell formed when individual cells merge
Tumor = an abnormal growth
A giant cell tumor (GCT) of bone is a benign (noncancerous) bone tumor that typically develops near the joints of the knee, wrist, shoulder, or spine. At The Spine Hospital at The Neurological Institute of New York, we specialize in giant cell tumors of the spine.
The spine is composed of bones called vertebrae. The cervical vertebrae are located in the neck; the thoracic vertebrae are in the upper and middle back, and the lumbar vertebrae form the spine in the lower back. Below the lumbar vertebrae, at the base of the spine, are several vertebrae fused into one bone called the sacrum. Giant cell tumors can occur at any of these spinal levels–the cervical spine, thoracic spine, lumbar spine, or the sacrum.
Bone tumors are classified as primary or secondary. Primary bone tumors arise originally from bone tissue, while secondary bone tumors have spread to the bone from a tumor elsewhere. GCTs are primary bone tumors. In the United States, GCTs make up about 5% of all primary bone tumors.
The benign nature of GCTs means that they tend not to spread. Rarely, however, they do spread to the lungs. But even this spread is usually “benign”: the tumor does not spread anywhere else in the body, and can be removed successfully from the lung. It is possible, but rare, for GCTs to become malignant (cancerous).
Giant cell tumors get their name from a type of cell in the tumor. “Giant cells” form when many other cells merge. They are also found in other bone tumors, as well as in normal bone. But a giant cell tumor has many of these giant cells intermixed with more typical cells.
One common symptom of a spinal giant cell tumor is pain at the tumor site.
Other symptoms may occur if the tumor compresses the spinal cord or spinal nerves. In the sacrum, GCTs may cause bowel or bladder incontinence, leg weakness, or sexual dysfunction. At the other spinal levels, symptoms vary depending on the tumor’s location and size. They may include arm or leg weakness, numbness, tingling, or bowel or bladder dysfunction.
Occasionally, a tumor can weaken a vertebra to such an extent that the vertebra breaks after a relatively minor trauma. This is called a pathologic fracture.
Causes and Risk Factors
The causes of giant cell tumors are not well understood. They do not run in families, and there are no known environmental risk factors.
Giant cell tumors are more common in women than in men, and generally occur in the third and fourth decade of life.
Tests and Diagnosis
Giant cell tumors can be identified on several types of imaging scans:
- X-ray (also known as plain films) –test that uses invisible electromagnetic energy beams (X-rays) to produce images of bones. Soft tissue structures such as the spinal cord, spinal nerves, the disc and ligaments are usually not seen on X-rays, nor on most tumors, vascular malformations, or cysts. X-rays provide an overall assessment of the bone anatomy as well as the curvature and alignment of the vertebral column. Spinal dislocation or slippage (also known as spondylolisthesis), kyphosis, scoliosis, as well as local and overall spine balance can be assessed with X-rays. Specific bony abnormalities such as bone spurs, disc space narrowing, vertebral body fracture, collapse or erosion can also be identified on plain film X-rays. Dynamic, or flexion/extension X-rays (X-rays that show the spine in motion) may be obtained to see if there is any abnormal or excessive movement or instability in the spine at the affected levels.
- Magnetic resonance (MR) imaging scan: uses radio waves and a magnet to produce images of organs and tissues
- Computed tomography (CT) scan: uses X-rays and a computer to produce cross-sectional images of bones and other structures
A CT-guided needle biopsy may help confirm the diagnosis, which helps in treatment planning. In a needle biopsy, a hollow needle is inserted through the skin into the tumor. The needle is used to remove a sample of tumor tissue, which can be analyzed in a laboratory. Needle biopsies of spinal giant cell tumors are done with CT guidance to ensure the safety of surrounding structures, like spinal cord and nerves.
Though GCTs are benign tumors that do not usually spread, they are sometimes described as locally aggressive. This means that they invade and destroy surrounding bone tissue, and they tend to recur after treatment. Complete surgical removal gives the best chance of avoiding recurrence, and is the treatment of choice for giant cell tumors whenever possible.
Depending on the tumor location, surgical options include:
- Anterior cervical corpectomy
- Cervical laminectomy
- Thoracic corpectomy
- Thoracic laminectomy
- Lumbar laminectomy
- Lumbar corpectomy
- Microsurgical tumor removal
- Stereotactic radiosurgery
Spinal fusion and stabilization with metallic implants is often performed following complete tumor removal.
Depending on the location and spread of the tumor, complete removal of a spinal GCT may not be safely possible. In such cases, several options are available. Subtotal (less than total) removal may help, especially when followed by focused or stereotactic radiation therapy. A nonsurgical procedure called embolization can slow the tumor’s growth by injecting a glue-like substance into its blood vessels, shutting off its blood supply.
The experienced neurosurgeons at The Spine Hospital at The Neurological Institute of New York can tailor a treatment plan to each individual and situation.